In situ venous valve device and method of formation

ABSTRACT

A venous valve device and method of formation are described to provide antegrade blood flow in the deep venous vessels of the leg or in other venous vessels of the body having incompetent or irreversibly dysfunctional valves. A venous valve is formed in situ from autologous vein conduit not having a valve present locally. An overlap region is formed by attaching two opposing walls of the vein together in a generally axial direction forming two tubular regions. One region provides antegrade blood flow and the other region provides a sinus cavity that is filled during the initiation of retrograde blood flow. A valve cusp is formed by attaching vessel wall together forming a commissure that extends between the two overlap regions. A single valve cusp moves toward the sinus cavity to allow antegrade blood flow and moves away from the sinus cavity to block retrograde blood flow. Inlet and outlet transition regions can be formed to provide hemodynamic antegrade blood flow through the valve. The autologous tissue valve remains endothelialized to prevent thrombus deposit in the valve. The venous valve can also be formed from biological tissue from an autologous, heterologous, or other tissue source and implanted interpositionally at the site of valvular incompetency.

BACKGROUND OF THE INVENTION

[0001] 1. Field of Invention

[0002] The present invention relates to a device and method for avascular valve for the vascular system and more specifically for thevenous vascular system of the human body and a method for forming thevenous valve and more specifically for forming the venous valve from anative vein that may have been enlarged diametrically within the patientcausing the naturally occurring venous valve to become incompetant.

[0003] 2. Description of Prior Art

[0004] Venous valves are found within native venous vessels and are usedto assist in returning blood back to the heart in an antegrade directionfrom all parts of the body. The venous system of the leg for exampleincludes the deep venous system and the superficial venous system, bothof which are provided with venous valves which are intended to directblood toward the heart and prevent backflow or retrograde flow which canlead to blood pooling or stasis in the leg. Incompetent valves can alsolead to reflux of blood from the deep venous system to the superficialvenous system and the formation of vericose veins. Superficial veinswhich include the greater and lesser saphenous veins have perforatingbranches in the femoral and popliteal regions of the leg that directblood flow toward the deep venous system and generally have a venousvalve located near the junction with the deep system. Deep veins of theleg include the anterior and posterior tibial veins, popliteal veins,and femoral veins. Deep veins are surrounded in part by musculaturetissue that assist in generating flow due to muscle contraction duringnormal walking or exercising. Veins in the lower leg have a staticpressure while standing of approximately 80-90 mm Hg and this pressurecan be reduced during exercise to 60-70 mm Hg. Despite exposure to suchpressures, the valves of the leg are very flexible and can close with apressure drop of less than one mm Hg. Due to the endothelial covering onthe venous valves, they are able to remain patent and resist thrombosiswith blood flow rates of less than 50 ml/min found typically in some ofthe smaller veins of the lower leg. Although the present invention hasdirect application to the treatment of venous valvular dysfunction ofthe leg, it is understood that the invention is not limited to thisapplication and can be applied equally well to the treatment of veinsthroughout the human body as well as other tubular elements of the bodyrequiring a valve.

[0005] Veins typically in the leg can become distended from prolongedexposure to excessive pressure and due to weaknesses found in the vesselwall causing the natural venous valves to become incompetent leading toretrograde blood flow in the veins. Such veins no longer function tohelp pump or direct the blood back to the heart during normal walking oruse of the leg muscles. As a result, blood tends to pool in the lowerleg and can lead to leg swelling and the formation of deep venousthrombosis and phlebitis. The formation of thrombus in the veins canfurther impair venous valvular function by causing valvular adherence tothe venous wall with possible irreversible loss of venous function.Continued exposure of the venous system to blood pooling and swelling ofthe surrounding tissue can lead to post phlebitic syndrome with apropensity for open sores, infection, leading to possible limbamputation.

[0006] Repair and replacement of venous valves presents a formidableproblem due to the low blood flow rate found in native veins, the verythin wall structure of the venous wall and the venous valve, and theease and frequency of which venous blood flow can be impeded or totallyblocked for a period of time. Surgical reconstruction techniques used toaddress venous valve incompetence involve venous valve bypass using asegment of vein with a competent valve, venous transposition to bypassvenous blood flow through a neighboring competent valve, andvalvuloplasty to repair the valve cusps. These surgical approaches aredescribed in medical journals and in standard surgical text books. Thesesurgical techniques are highly technique dependent and difficult toperform by a highly trained vascular surgeon.

[0007] The presence of a low or intermittent blood flow rates found inthe veins of the lower leg requires that any suitable venous valvereplacement contain an endothelial covering to protect the vesselagainst thrombosis. Blood stoppage for a period of time in contact withmost foreign material can result in thrombus formation, and ensuingfailure of any venous valve constructed of a polymeric material or somebiomaterials.

[0008] Quijano describes in U.S. Pat. No. 5,500,014 the use of abiological valvular prosthesis that is obtained from the jugular vein ofan animal. The valve is chemically fixed to give it strength. The fixingprocess tends to cause such valves to be stiff and calcification hasbeen known to occur at flexation sites. Another problem with valves ofthis type is their lack of forming a stable endothelium with theresulting formation of thrombus when blood flow is impeded ortemporarily blocked. Others have tried constructing venous valves out ofa biological tissue material obtained from another species or the samespecies. Some tissues that have been used include pericardium and venoustissue treated with a crosslinking treatment. These devices havesuffered problems associated with calcification, tissue degradation,tissue rejection, acute thrombosis, long term thrombosis, and valvularfailure due to mechanical dysfunction.

[0009] Another vascular prosthesis that is constructed out of polymericor metallic components is described by Camilli is U.S. Pat. No.5,358,518. He describes a movable rigid or semi-rigid plate that pivotsand allows unidirectional blood flow through the venous tube. Thebiomaterials used in the device of Camilli will not form a stableendothelium on the blood flow surface; due to the low blood flow andoften times interrupted blood flow found within the venous system, thisdevice will be prone to thrombosis and failure.

[0010] Laufer (U.S. Pat. No. 5,810,847) describes an appliance that isconstructed out of a biomaterial that is attached to the cusps of anexisting venous valve. Such a polymeric appliance will have a propensityto thrombosis in the low blood flow conditions found in the venoussystem. Also, many patients with venous problems do not have suitablevalves onto which the appliance described by Laufer can be attached.

[0011] Lane describes in U.S. Pat. Nos. 5,147,389 and 4,904,254 andShifrin describes in U.S. Pat. No. 5,476,471 devices that are intendedto surround the outer surface of incompetent or insufficient venousvalves. These devices are intended to reduce the diameter of the vesselin the region of the incompetent valve allowing the natural cusps toapproximate each other leaving the valve commissures intact. For thesedevices to work properly, the valves of the vein must not be adherent tothe vessel wall, this adherent condition is often found when the vesselis exposed to deep venous thrombosis. This significantly limits thepatient population that can benefit from a device of this type.

[0012] A treatment for venous valvular dysfunction in patients that havehad their vein wall distended and their valves irreversibly damaged isneeded. The treatment should involve autologous tissue such that anendothelial layer is present in blood contact and thrombosis due to lowflow is not of concern. The treatment should be easily performed so thatpatients with tissue edema and ulcers can tolerate the intervention andheal the area being accessed. The treatment should be applicable tothose patients who have had deep venous thrombosis, phlebitis, or othervascular trauma and have irreversibly lost venous valvular function.

SUMMARY OF THE INVENTION

[0013] The present device and method for forming a venous valveovercomes the disadvantages of prior art prosthetic venous valvesconstructed out of crosslinked biological tissue, polymeric, or otherbiomaterials and it also overcomes problems associated with the surgicalrepair of venous valves. The venous valve of the present invention isconstructed directly from the distended vein of a patient and it doesnot require the presence of an existing venous valve. Since the valve ofthe present invention is being constructed from autologous vein tissuewith the natural endothelium of the vein in immediate contact with theblood, thrombosis such as that associated with biologic, polymeric, orother biomaterial constructed prosthesis is not a major concern. Thevenous valve of the present invention is configured from a segment ofdistended vein forming a new venous valve within the distended vein.Problems associated with irreversible valvular destruction or adhesionto the vessel wall due to deep venous thrombosis, phlebitis, or othervascular trauma will not influence the formation of the valve of thepresent invention within a distended vein. The method of forming thevenous valve of the present invention is intended to be much simplerthan venous valve bypass, valvular transposition, or valvuloplasty asperformed by the peripheral vascular surgeon. The present method offorming the venous valve is intended to require only a minimallyinvasive surgery involving an easier and direct surgical procedure thatcan be applied to almost any distended vein.

[0014] The venous valve of the present invention involves identifying asegment of cylindrical tubular shaped distended vein and forming it intoa venous conduit with a working valve in it. The venous valve has anoverlap region that contains a through-flow member to allow antegradeblood flow through the venous valve and a sinus member which provides acavity that is filled during the initiation of retrograde flow. A singlevalve cusp is located between the overlap through-flow member and theoverlap sinus member. The valve cusp is capable of moving toward thesinus member to allow antegrade flow and moving to block thethrough-flow portion during the initiation of retrograde or back flow.The venous valve can also have an inlet transition region and it canhave an outlet transition region. The transition regions are intended toprovide a gradual tapering of the blood flow path from the distendedvein to the smaller diameter of the overlap region. The blood flowsurface of the through-flow and sinus portions of the overlap region,the transition regions, and the valve cusp are all endothelialized withthe natural endothelium found in the native distended vein.

[0015] The structure of the venous valve is most easily and clearlydescribed using cylindrical coordinates to describe the native distendedvein and its relationship to various aspects of the venous valve that isformed from it. A cross section taken through the distended vein on theinlet side of the venous valve and facing downstream can be assigned azero degree radian that intersects with the vein wall at a zero degreewall. Similarly one can identify a 90, 180, 270, or another degree wallalong the vein wall at the inlet end of the overlap region. A zerodegree line can be identified as that portion of the distended vein wallthat extends axially and passes through the zero degree wall. The zerodegree line describes venous wall material that may be sewn, sutured,stapled, bonded by adhesive, or attached in another way to anotherportion of venous wall material. The zero degree line can include theinner or outer surface of the vessel wall or it can include the entirevessel wall. Similarly, 90, 180, and 270 degree lines can also beidentified. A first quadrant can be identified as the venous vessel wallthat extends from the zero degree line to the 90 degree line. Similarly,a second, third, and fourth quadrant can also be identified.

[0016] For ease of describing the present invention, the vessel wall hasbeen divided into quadrants, however it is understood that the vesselcould be divided into a much greater number of sectors, each sectordescribing a smaller angle than 90 degrees and a smaller wall surfacearea than is occupied by a quadrant. Also, for ease of understanding, awall line has been defined for the purposes of the drawings as extendingapproximately parallel to the centerline or axis of a tubular vessel. Itis understood that for the venous valve of the present invention that awall line is only required to have a component in the axial direction.

[0017] The venous valve of the present invention is intended to directblood flow in a single antegrade direction from upstream to downstream,from its inlet to its outlet, toward the heart. The overlap region ofthis invention has an inlet and outlet end and an axial overlap length.In one embodiment of the present invention a segment of distended veinwith an axial overlap length is identified. The zero degree line of thevein is brought into contact with the 180 degree line and the vein wallsare attached using an attachment means which includes suturing orsewing, staples, adhesives or other bonding agents, thermal or otherforms of welding, or other physical or chemical attachment mechanisms.It is understood that reference to the zero degree line, 180 degree lineor other degree lines, points, or quadrants are approximate referencesand deviations from these lines, points, or quadrants are allowed withinthe framework of the present invention. For ease of understanding theinvention is being described such that a wall line extendingapproximately parallel to the axis and extending throughout the overlapregion is attached to another parallel wall line. It is understood thatthe wall lines need not be parallel to the axis and they need not extendthroughout the overlap region to describe the present invention. Todescribe the present invention only a portion of such a wall line needbe attached to a portion of another wall line. The 90 and 270 degreelines are brought into contact and the walls are attached usingattachment means. At the inlet end of the overlap region, the first,second, and fourth quadrants are attached using attachment means. At theoutlet end of the overlap region, the first and fourth quadrants areattached together.

[0018] The overlap region has a through-flow member defined by the thirdand fourth quadrant. At the outlet end of the overlap region is anopening between the first and second quadrant that provides entry intothe sinus member of the overlap region. The first and fourth quadrantwhich are attached at the outlet end of the overlap region serve as thevalve cusp. This attachment is not required to occur at the outlet endof the overlap region. It is understood that a portion of the first andfourth quadrants are attached together to form a member of the valvecusp. The cusp moves into approximation with the second quadrant duringantegrade flow, and moves into approximation with the third quadrantduring the initiation of retrograde or back flow allowing the sinuscavity or member to fill with blood. During antegrade blood flow throughthe venous valve, blood is directed through the through-flow member fromthe inlet to the outlet of the overlap region. This occurs for examplein the legs during muscular contraction associated with walking orrunning or when the leg is in a reclined position and the pulsing of theheart moves the blood throughout the body including blood return fromthe legs. During the period of time that blood is not moving in anantegrade direction such as during standing or between periods of musclecontraction, blood is prevented from moving in a retrograde direction orfrom backflow or reflux by the venous valve. At the outlet end of theoverlap region some backflow will go into the sinus member of the venousvalve causing the sinus member to fill. This occurs as retrograde bloodflow through the through-flow member generates fluid shear stresses uponthe valve cusp causing it to move in the direction of flow. Due togeometrical constraints of the valve cusp with the inner and outer wallsof the overlap region, the valve cusp also moves away from the secondquadrant and allows blood to enter the sinus member of the overlapregion. A small pressure difference between the blood at the inlet endof the sinus member and the outlet end of the sinus member which is deadended and will not allow further retrograde blood flow, provides thedriving force for blood entry into the sinus member. The valve cusp willmove toward the third quadrant causing the through-flow member to closeand stop further backflow or retrograde flow.

[0019] The four quadrants of the overlap region can be supported eitherwithin the walls or on the surface of the walls to resist possiblestretching. A suture, thread, ribbon or other supportive means can besewn, sutured, bonded, or placed along the third quadrant of thethrough-flow member at the inlet end to ensure that the entrance to theoverlap region does not enlarge with continued exposure to pressure.Similarly, a supportive means can be attached to or placed along thesecond quadrant of the sinus member or the third quadrant of thethrough-flow member at the outlet end to ensure that further venousdistension does not prevent the valve cusp from providing closure to thethrough-flow member. Additionally, further supportive means can beplaced throughout any of the four quadrants to support both thethrough-flow member and sinus member.

[0020] The venous valve of the present invention can have an inlettransition region to connect the inlet end of the overlap region to thecylindrically shaped distended vein and an outlet transition region toconnect the outlet end of the overlap region to the cylindrically shapeddistended vein. These transition regions provide a tapered shape forblood to follow from the large distended vein to the smaller diameterfor the through-flow member of the overlap region and back to the largediameter of the distended vein. Several possible ways of forming thetransition regions are possible and are provided in the presentinvention in various embodiments to the invention.

[0021] The inlet transition region will be described at a locationadjacent to the inlet end of the overlap region and at a locationapproximately half way between the inlet end of the overlap region andthe cylindrically shaped native distended vein. Near the inlet end ofthe overlap region, the transition region has its zero degree wall inapproximation to the 180 degree wall, and the 90 degree wall is incontact with and attached to the 270 degree wall. At the locationhalfway between the overlap region and the cylindrically shaped vein,approximately the 45 degree wall is attached to the 315 degree wall.This provides approximately a linear tapering of the diameter of theinlet transition region from the overlap region to the cylindricallyshaped vein. It is understood that attachments can be made continuouslyalong the transition region, not just at the two points that have beenidentified. Any excess material from the first and fourth quadrant thatextends into the lumen of the transition region or extends out from thelumen of the transition region can be trimmed off or removed, providedthat a leak tight attachment has been made along the transition region.The outlet transition region can be constructed in a manner similar tothat of the inlet transition region.

[0022] An alternate method of constructing the inlet transition regionagain can be examined at two locations with interpolation orextrapolation of the results to other locations along the transitionregion. At the junction of the inlet transition region with the inletend of the overlap region the zero degree point is in contact with andattached to the 180 degree point and the first quadrant can be attachedto the second quadrant. At a location approximately half way between theinlet end of the overlap region and the cylindrically shaped distendedvein, the 45 degree point is in contact with and attached to the 135degree point. It is anticipated that a continuum of points are attachedalong the transition region such that a generally tapered shape for thetransition region is formed from the overlap region to the cylindricallyshaped vein.

[0023] In another embodiment for forming the overlap region, a segmentof cylindrically shaped distended vein is placed into a flattenedconformation and the first and fourth quadrants are attached togetheralong the inlet end of the overlap region and cut at the inlet end ofthe overlap region through the first and fourth quadrant. Similarly, thedistended vein is attached together along the outlet end of the overlapregion and cut through the first and fourth quadrants of the outlet endof the overlap region. The zero degree line is placed into contact withand attached to the 180 degree line from the inlet end to the outlet endof the overlap region. This is accomplished by inverting the first andfourth quadrants into the second and third quadrants. This forms twoseparate tubes in the overlap region one for through flow of bloodbetween the third and fourth quadrant and one to serve as the sinusmember of the overlap region between the first and second quadrant. Atthe inlet end of the overlap region the first and second quadrants areattached together. This is necessary to prevent antegrade blood flowfrom entering into the sinus member of the overlap region. The 90 and270 degree lines are attached together from the inlet end to the outletend of the overlap region to hold the sinus member into immediatecontact with the through-flow member of the overlap region. Thisprovides a single lumen between the third and fourth quadrant forthrough flow through this member of the overlap region. At the outletend of the overlap region is located the leading edge of the singlevalve cusp that is made up of the first and fourth quadrants of theoverlap region. The valve cusp is completely endothelialized along withall blood contact surfaces of the venous valve. The inverted nature ofthe leading edge provides this embodiment with a particularly goodresistance to thrombosis. The walls of the valve can be supported asdescribed earlier with the other embodiments.

[0024] The inlet transition regions for the embodiment just discussedcan be formed by attaching the first and fourth quadrants together on aline that extends from a point of attachment of the 90 and 270 degreewalls at the inlet end of the overlap region along a beveled pathway toa zero degree wall on the cylindrically shaped distended vein. Thebeveled or tapered pathway provides a smooth blood flow transition fromthe distended vein to the overlap region. Any excess venous tissue thatextends from the beveled attachment line to the zero degree line in thetransition region can be trimmed off or removed. The outlet transitionregion can be similarly constructed.

[0025] It is noted that the construction of the venous valve of thisinvention requires some means for attachment between various quadrantsof the venous wall. In forming the attachment of the zero degree linewith the 180 degree line of the first embodiment, or attaching onequadrant to another along an inlet or outlet end of the overlap region,or for forming many other of the wall attachments or wall cuts, thedistended vessel can be placed in a flattened position to allow theattachments to be made easier. The venous valve of this invention lendsitself well to a mechanism that will assist the surgeon in making theattachments and cuts and allow the formation of this venous valve to bemade quickly and consistently.

[0026] It is understood that the inlet and outlet transitions regionembodiments can be interchanged with each other when possible. It isunderstood that other possible variations of the overlap region ortransition regions may exist that are not shown by the drawings but areindeed taught by this patent application and should be considered aspart of the teachings of this disclosure. The teachings of this patentapplication are not limited to the drawings and embodiments includedherein.

[0027] It is further understood that the venous valve of the presentinvention can be constructed out of biological tissue such as venoustissue from animal sources, autologous tissue such as pericardium orvenous tissue from another part of the body, or polymeric materials suchas those used in vascular grafts. A venous valve of the presentinvention can be constructed as per the methods taught in the presentdisclosure and the resultant venous valve can be implantedinterpositionally into a vein of a person at the venous site thatrequires a functioning venous valve. An embodiment such as this providesthe advantage of simplicity of design and ease of formation.

BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Other objects of the present invention and many of the attendantadvantages of the present invention will be readily appreciated as thesame becomes better understood by reference to the following detaileddescription when considered in connection with the accompanyingdrawings, in which like reference numerals designate like partsthroughout the figures thereof and wherein:

[0029]FIG. 1 is an isometric view of distended vein segment;

[0030]FIG. 2 is an isometric view of a first embodiment of the venousvalve of this invention;

[0031]FIG. 3A is an isometric view of an overlap region in an earlystage of formation;

[0032]FIG. 3B is an isometric view of an overlap region from an inletend;

[0033]FIG. 3C is an isometric view of an overlap region from an outletend;

[0034]FIG. 4 is an isometric view of an overlap region with wallsupport;

[0035]FIG. 5A is a partially sectioned view of the first embodiment ofthe venous valve of this invention in a flattened state;

[0036]FIG. 5B is a sectional view of the inlet or outlet distended veinin a flattened state;

[0037]FIG. 5C is a partially sectioned view of the first embodiment ofthe venous valve of this invention conformed for blood flow;

[0038]FIG. 5D is a sectional view of the inlet or outlet distended veinconformed for blood flow;

[0039]FIG. 6A is a sectional view of the inlet end of the overlap regionin a flattened state;

[0040]FIG. 6B is a sectional view of the inlet end of the overlap regionduring antegrade blood flow;

[0041]FIG. 7A is a sectional view of the outlet end of the overlapregion during venous valve formation;

[0042]FIG. 7B is a sectional view of the outlet end of the overlapregion during antegrade blood flow;

[0043]FIG. 7C is a sectional view of the outlet end of the overlapregion during retrograde blood flow;

[0044]FIG. 8A is a sectional view of one inlet transition regionembodiment near the overlap region during venous valve formation;

[0045]FIG. 8B is a sectional view of one inlet transition regionembodiment near the inlet distended vein during venous valve formation;

[0046]FIG. 8C is a sectional view of one inlet transition regionembodiment near the overlap region during antegrade blood flow;

[0047]FIG. 8D is a sectional view of one inlet transition regionembodiment near the inlet distended vein during antegrade blood flow;

[0048]FIG. 9A is a sectional view of one outlet transition regionembodiment near the overlap region during venous valve formation;

[0049]FIG. 9B is a sectional view of one outlet transition regionembodiment near the inlet distended vein during venous valve formation;

[0050]FIG. 9C is a sectional view of one outlet transition regionembodiment near the overlap region during antegrade blood flow;

[0051]FIG. 9D is a sectional view of one outlet transition regionembodiment near the inlet distended vein during antegrade blood flow;

[0052]FIG. 10A is a sectional view of a second inlet transition regionembodiment near the overlap region during venous valve formation;

[0053]FIG. 10B is a sectional view of a second inlet transition regionembodiment near the outlet distended vein during venous valve formation;

[0054]FIG. 10C is a sectional view of a second inlet transition regionembodiment near the overlap region during antegrade blood flow;

[0055]FIG. 10D is a sectional view of a second inlet transition regionembodiment near the outlet distended vein during antegrade blood flow;

[0056]FIG. 11A is a partially sectioned view of an alternate embodimentof the venous valve of this invention in an early stage of formationwith early attachment lines;

[0057]FIG. 11B is a sectional view of the inlet end of the overlapregion during an early stage or formation;

[0058]FIG. 11C is a partially sectioned view of an alternate embodimentof the venous valve of this invention in an early stage of formationwith overlap region and transition region cuts;

[0059]FIG. 11D is a partially sectioned view of an alternate embodimentof the venous valve of this invention in an early stage of formationwith an inverted fold;

[0060]FIG. 11E is a partially sectioned view of an alternate embodimentof the venous valve of this invention;

[0061]FIG. 12 is a sectional view of an inlet end of an overlap regionof an alternate embodiment of the venous valve of this invention withantegrade blood flow;

[0062]FIG. 13A is a sectional view of an outlet end of an overlap regionof an alternate embodiment of the venous valve of this invention withantegrade blood flow;

[0063]FIG. 13B is a sectional view of an outlet end of an overlap regionof an alternate embodiment of the venous valve of this invention withretrograde blood flow into an overlap sinus member;

[0064]FIG. 14A is a sectional view of an alternate inlet transitionregion embodiment near the overlap region with antegrade blood flow;

[0065]FIG. 14B is a sectional view of an alternate inlet transitionregion embodiment near the inlet distended vein with antegrade bloodflow;

[0066]FIG. 15A is a sectional view of an alternate outlet transitionregion embodiment near the overlap region with antegrade blood flow;

[0067]FIG. 15B is a sectional view of an alternate outlet transitionregion embodiment near the outlet distended vein with antegrade bloodflow;

[0068]FIG. 16 is an isometric view of an alternate embodiment of thevenous valve of this invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0069] An embodiment of the venous valve of the present invention isformed from an approximately cylindrically shaped segment of distendednative vein and the formation occurs with the vein in place in itsnaturally occurring in situ position. Once the venous valve has beenformed, it can be contiguous with or it can be attached to native veintissue both upstream and downstream from the venous valve. The structureof the venous valve and the methods for its construction are most easilyand accurately described by referring to a cylindrical coordinate systemto describe various properties or characteristics of the native vein andapply these characteristics to the formation of the venous valve of thepresent invention.

[0070] A venous valve of an embodiment of the present invention couldalso be formed from a segment of vein or other tissue taken from anysuitable location within the same patient that requires the venousvalve. The segment of vein containing the valve formed by the methods ofthe present invention could then be transsected from its natural venouslocation or other location and interposed into the autologous vein thatrequires the venous valve. Autologous tissue such as pericardium orother tissue conduits could also be used to form the venous valve of thepresent invention. Pericardial tissue could be formed into anapproximate cylindrical shape or tubular shape and formed into the veinof the present invention as described by the present disclosure. Such aformed venous valve would be implanted by standard interpositionalsurgical procedure into the vein of a patient requiring a venous valveby simply transsecting a portion of the patients vein and interposing asegment of tissue containing a valve formed by the present inventioninto its place using standard surgical technique or other less invasivetechnique. A venous valve of the one described in the present inventioncould also be formed out of biological tissue obtained from an animalvenous conduit, a venous conduit from another human, other suitableconduit, pericardial tissue, or other suitable tissue. Such tissue couldbe treated using a crosslinking agent such as glutaraldehyde or othercrosslinking or strengthening agent to enhance strength and reduce theantigenic character of the tissue. The biological tissue or tissueconduit could then be formed into a venous valve using the methodsdescribed in the present invention. The formed venous valve of thepresent invention could then be interposed into the vein of a patientrequiring a venous valve. The venous valve of the present inventioncould also be formed out of polymeric or a composite material includingpolymers, metals, ceramics, or other biologically compatible materials.Such polymeric or composite materials could be formed into anapproximately tubular shape and further formed into the venous valve ofthe present invention using the methods taught in this disclosure. Suchtubular means from which the venous valve of the present invention canbe constructed therefore include autologous vein, autologous tissueformed into a tubular shape of approximately round or other crosssectional shape, non-autologous biological conduit, non-autologousbiological tissue, polymeric conduit, polymeric fabric, polymericsheeting, or polymeric material formed into a conduit, or a compositematerial conduit.

[0071]FIG. 1 is an isometric view of a distended vein segment 5 or othertubular conduit that can be formed into the venous valve of thisinvention with an inner surface 10, an outer surface 15, a vein wall 20,a wall area 21, and a distended vein segment diameter 22. The distendedvein segment 5 can be formed into the venous valve of the presentinvention. The distended vein segment 5 can also be transsected andreplaced by a venous valve of the present invention formed from anothersuitable biocompatibe material formed into a tube and being described bysimilar nomenclature. The distended vein segment 5 is shown extendingfrom an inlet vein-transition junction 25 to the outlet vein-transitionjunction 30. The distended vein segment 5 is a portion of the autologousvein that requires a venous valve. At or near the inlet vein-transitionjunction 25 is found a zero degree radian 35 extending from a centerline40 through an inner surface zero degree point 45 to an outer surfacezero degree point 50. A cut-away view is shown in FIG. 1 to provide aneasier understanding of the structure of the vein or other tubularstructure and to establish a terminology that will be used later todescribe the present invention. An inner surface zero degree line 55 isa line that passes along the inner surface 10 of the vein and travelsgenerally parallel to the centerline 40 in an axial direction passingthrough the inner surface zero degree point 45. Similarly, an outersurface zero degree line 65 is a line generally parallel to thecenterline 40 and passes along the outer surface 15 through the outersurface zero degree point 50. The vein wall along the zero degree radian35 extending from the inner surface zero degree point 45 to the outersurface zero degree point 50 is referred to as zero degree wall 70. Azero degree wall line 75 is defined as the zero degree wall 70 thatfollows the wall of the vein along a line generally in a directionparallel to the centerline 40 and passing through the zero degree wall70. The zero degree wall 70 and zero degree wall line 75 are defined toallow an alternate description of attachment between two vein walls tobe made. The zero degree wall line includes the inner 55 and outer 60surface zero degree lines plus the wall in between. Attachment between azero degree wall line 75 and a vein wall 20, for example, is understoodto mean that either the inner surface 10, the outer surface 15, or thevenous tissues between the inner 10 and outer 15 surfaces of the venouswall 20, or the vein wall 20 including both surfaces along the zerodegree wall line 75 can be attached to another vein wall 20. In asimilar manner a 90 degree wall 80 can be identified for the distendedvein segment 5 at a location of intersection between a 90 degree radian85 and the vessel wall 20. The 90 degree radian 85 is rotated clockwise90 about the centerline 40, an angle 95 of 90 degrees from the zerodegree radian 35 and with respect to an antegrade flow direction 100. A90 degree wall line 105 can then be identified in a manner similar tothat described for the zero degree wall line 75 and the vein wall 20that extends between the zero 75 and 90 (105) degree wall lines isconsidered the first quadrant 110. Similarly, a 180 (115) and 270 (120)degree wall, a 180 (125) and 270 (130) degree wall line, and a second135, third 140, and fourth 145 quadrant can be identified. In a mannersimilar to that discussed earlier, an inner surface 90 (150), 180 (155),and 270 (160) degree point and an outer surface 90 (165), 180 (170), and270 (175) degree point can be defined. Similarly, an inner surface 90(180), 180 (185), and 270 (190) degree line and an outer surface 90(195), 180 (200), and 270 (205) degree line can be identified.

[0072] It is understood that the zero, 90, 180, and 270 degree lines forthe inner surface, outer surface, and wall as they are discussed in thisdisclosure are not required to be exact but are used only for ease ofunderstanding. Actual attachment lines for the valve of the presentinvention can vary from what is described in this disclosure byapproximately 90 degrees or more depending upon the condition of thenative distended vein, the accuracy of the procedure, and the ability ofthe present venous valve formation methods to allow for considerablemodification without changing the overall teachings and function of thevalve. The description provided in FIG. 1 is intended to provide asimplified system to describe the device and method of formation of thepresent venous valve in an understandable way. The distended veinsegment 5 was divided into quadrants for ease of description although itis understood that the vein segment could be divided into more numeroussectors (not shown), each sector having less than 90 degrees and havinga wall surface area less than a quadrant. Although the quadrants used inthis disclosure are positioned in a clockwise 90 manner, it isunderstood that the location of the first quadrant 110 was arbitrarilychosen. Individual sectors which could have been used to describe thevenous valve of the present invention can be assigned arbitrarily aboutthe distended vein segment 5 to describe the line and wall attachmentsof the present invention. It is further within the understanding of thepresent invention that a portion of an inner 10 or outer 15 surface orwall area 21 of a quadrant or a sector could be attached to a portion ofan inner 10 or outer 15 surface or wall area 21 of another quadrant overa specific area without changing the function of the venous valve. Sucha surface attachment or a wall area attachment is understood to beincluded within the teachings of the present invention. It is alsounderstood that an attachment of an inner or outer surface line or awall line to another surface or wall line involves more of the vein wallthan simply a line. It is assumed that a portion of the vein wall 20 oneach side of such a line attachment is involved in the attachment inorder to provide strength to the attachment. A surface line attachmentor a wall line attachment therefore is understood to involve a wall area21 in forming the attachment.

[0073]FIG. 2 is an isometric view of a first embodiment of the venousvalve 210 of the present invention. The venous valve of this embodimentis made up of three separate regions, the inlet transition region 215,the overlap region 220, and the outlet transition region 225. The venousvalve 210 of one embodiment is joined contiguously to the inletdistended vein 230 at the inlet vein-transition junction 25 and to theoutlet distended vein 235 at the outlet transition-vein junction 30. Theoverlap transverse dimension 240 is smaller than the inlet distendedvein diameter 245 or the outlet distended vein diameter 250. The inlettransition region 215 provides a smooth blood flow transition in anantegrade flow direction 100 from the larger inlet distended veindiameter 245 to the smaller overlap transverse dimension 240 at theoverlap inlet end 255. The outlet transition region 225 provides asmooth blood flow transition in the antegrade flow direction 100 fromthe overlap outlet end 255 to the outlet transition-vein junction 30. Inthe overlap region 220, the inner surface zero degree line 55 is shownin contact with the inner surface 180 degree line 185, and having aninner surface zero and 180 degree line attachment 265. This innersurface zero and 180 degree line attachment 265 can involve a surfaceattachment method such as a thermal or laser weld, a biological glue oradhesive, or other surface attachment means. Additionally, the innersurface zero and 180 degree line attachment 265 in the overlap region220 can involve the entire vessel wall, by attaching the zero (75) and180 (125) degree wall lines with sutures, staples, or any other wallattachment means including laser, thermal, or other fusion methods thatwill attach the zero degree wall line 75 and the 180 degree wall line125 together in the overlap region 220. An example of such means 268 isshown in FIG. 2 extending in the overlap region 220. This inner surfacezero and 180 degree line attachment 265 is shown to extend from theoverlap inlet end to outlet end but it is understood that it can extendover only a portion of this overlap region 220 without affecting thefunction of the valve of the present invention. The outer surface zero65 and 180 (200) degree lines are also shown. An outer surface 90 and270 degree line attachment 270 is also present in the overlap region220. This outer surface 90 and 270 degree line attachment 270 can bemade by attaching the outer surfaces together using thermal or laserbonding methods or with biological glues or adhesives. Outer surface 90and 270 degree line attachment 270 can also be made using sutures,staples, fusion methods, or other attachment means to attach the 90degree wall line 105 to the 270 degree wall line 130 with attachmentextending through a portion of or through the entire vessel wall 20.This outer surface 90 and 280 degree line attachment 270 can beintermittant and can extend over only a portion of the length of theoverlap region 220 without affecting the function of the venous valve ofthe present invention.

[0074]FIG. 3A is an isometric view of the overlap region 220 of oneembodiment of the venous valve of the present invention in an earlystage of formation. The vein wall 20 that is to form the overlap region220 between the overlap inlet 255 and outlet 260 end has been partiallyflattened by allowing the first 110 and fourth 145 quadrant to bepositioned above the second 135 and third 140 quadrant, respectively.This allows the zero degree wall line 75 to lie directly upon the 180degree wall line 125 and allow ease of surface or wall attachment meansto hold the inner surface zero degree line 55 against the inner surface180 degree line 185. The outer surface zero 65 and 180 (200) degree lineand the antegrade flow direction 100 are shown. It is understood thatthe overlap region 220 may be flattened to a greater extent than isshown in FIG. 3A prior to forming the inner surface zero and 180 degreeline attachment 265.

[0075]FIG. 3B is an isometric view of the overlap region 220 showing theoverlap inlet end 255 of the venous valve 210 of this invention. Theinner surface zero and 180 degree line attachment 265 extends from theoverlap inlet end 255 to the overlap outlet end 260; this divisionalattachment divides the overlap region into two tubular members, onemember between the first 110 and second 135 quadrants, and anothermember between the third 140 and fourth 145 quadrants. The two tubularmembers provide two separate lumens or compartments without leakage ofblood across the divisional attachment. Such a divisional attachmentcould be formed by attachment of two sectors together instead ofquadrants as shown in the drawings for ease of description. An overlapinlet end first and second quadrant attachment 275 at the overlap inletend forms a closure attachment that prevents blood flow in an antegradeflow direction 100 from entering between the first 110 and second 135quadrant. This overlap inlet end first and second quadrant attachment275 can be made by attaching the inner surface 10 of the first 110 andsecond 135 quadrant using surface attachment means such as bondingagents or welding methods as described earlier or attachment can be madethrough the vein wall 20 of the first 110 and second 135 quadrants usingsutures, staples, fibers, or other wall attachment means. An example ofsuch surface or wall attachment means 278 is shown in FIG. 3B, and canbe formed of a suture or other material. An overlap inlet end first andfourth quadrant attachment 280 is also found at the overlap inlet end255; this attachment 280 prevents antegrade blood flow from enteringbetween the first 110 and fourth 145 quadrants. This overlap inlet endfirst and fourth quadrant attachment 280 forms a portion of the valvecusp attachment that is required to hold the walls of the first 110 andfourth 145 quadrants together over at least a portion of the wall. Thisoverlap inlet end first and forth quadrant attachment 280 can be made byattaching the outer surfaces 15 of the first 110 and fourth 145quadrants from the 270 (120) and 90 (80) degree wall to the zero degreewall 70 using surface attachment means on the outside surfaces of thefirst 110 and fourth 145 quadrants or using wall attachment means thatattach the vein wall of the first 110 and fourth 145 quadrants togetherat the overlap inlet end 255. The first 110, second 135, and fourth 145quadrants can all be attached together at the overlap inlet end 255using a single surface or wall attachment means, an example of which isshown by reference numeral 278. Attachment of the outer surface 90 (195)and 270 (205) degree lines from the overlap inlet end 255 to the overlapoutlet end 260 holds the outer surfaces 15 of the first 110 and fourth145 quadrants into approximation with each other throughout the overlapregion 220 and forms an approximation attachment. The 90 degree wallline 105 can be attached to the 270 degree wall line of the overlapregion 220 using attachment means including sutures, staples, or fusionmethods. An example of such attachment means 278 is shown in FIG. 3B,and can be formed of suture or other material.

[0076] The overlap inlet end 255 is shown as a transverse section thatextends in a direction perpendicular to the antegrade flow direction100. It is understood that the overlap inlet end can be positioned on abevel or at an angle with respect to the direction of flow in anantegrade direction 100. Additionally, the overlap inlet end first andsecond quadrant attachment 275 is not required to be located inimmediate apposition to the overlap inlet end first and fourth quadrantattachment 280. All reference numerals correspond to those elementspreviously or otherwise described.

[0077]FIG. 3C is an isometric view of the overlap region 220 showing theoverlap outlet end 260 of the venous valve 210 of the present invention.At the overlap outlet end 260, an overlap outlet end first and fourthquadrant attachment 285 is formed to attach the inner surfaces 10 (seeFIG. 1) of the first 110 and fourth 145 quadrants along the overlapoutlet end 260. This overlap outlet end first and fourth quadrantattachment 285 can be made using bonding agents, biological glues, orother adhesives, or it can be formed from a thermal, laser, or fusionprocess, or other surface method that bonds tissue surfaces or tissuewalls together. The overlap outlet end first and fourth quadrantattachment 285 can also be formed by sewing or suturing the vein wallstogether along the overlap outlet end or by using staples or other wallattachment means. An example of such surface or wall attachment means278 is shown in FIG. 3C, and can be formed of suture, staples, metallicor polymeric fibers, or other material. Laser fusion, thermal fusion,and other fusion methods can also be considered wall attachment meanssince they can extend into the central tissue found in the vein wall toachieve their attachment. The overlap outlet end first and fourthquadrant attachment 285 along with the overlap inlet end first andfourth quadrant attachment 280 (see FIG. 3B) form a valve cuspattachment that identifies one way of attaching the first 110 and fourth145 quadrants together. Such a valve cusp attachment can be formed usingattachment means to hold a portion of the inner surfaces 10 of the first110 and fourth 145 quadrants together or hold a portion of the walls ofthe first 110 and fourth 145 quadrants together such that they areattached and can function as a valve cusp 290. All reference numeralscorrespond to those elements previously or otherwise described.

[0078] The outer surface 90 and 270 degree line attachment 270 is shownholding the outer surface 90 degree line 195 in contact with the outersurface 270 degree line 205 from the overlap inlet end 255 to theoverlap outlet end 260. This outer surface 90 and 270 degree lineattachment 270 is an approximation attachment and is not required inthis embodiment to be continuous and can have intermittent attachmentsas long as the outer surfaces 15 of the first 110 and fourth 145quadrants are held in apposition with each other in the overlap region220. The inner surface zero and 180 degree line attachment 265 is shownin FIG. 3C to extend from the overlap inlet end 255 to the overlapoutlet end 260 and this divisional attachment could involve only aportion of the overlap region 220 as long as it forms two tubularmembers as shown in FIG. 3C within the overlap region 220 that do notleak substantial blood flow across this attachment 265. An overlapthrough-flow member 295 is formed by the third 140 and fourth 145quadrants of the overlap region 220 providing a passage for blood flowin an antegrade flow direction 100. An overlap sinus member 300 isformed by the first 110 and second 135 quadrants of the overlap region220. The second 135 and fourth 145 quadrants which are attached at theoverlap outlet end first and fourth quadrant attachment 285, form thevalve cusp 290 with a commissure 305 or leading edge of the valve cusp290 located at the overlap outlet end first and fourth quadrantattachment 285. During blood flow in an antegrade direction 100, thevalve cusp 290 is displaced toward the second 135 quadrant and the innersurface 10 (see FIG. 1) of the first quadrant 110 can come into contactwith the inner surface 10 of the second quadrant 135. Movement of thevalve cusp 290 during blood flow in an antegrade direction 100 providesa large overlap through-flow member diameter 310 and the leastresistance to blood flow. Antegrade blood flow can occur in the veins ofthe leg during leg muscle contraction and with the legs in a reclinedposition. Initiaition of blood flow in a retrograde flow direction 315in the overlap through-flow member 295 can initiate in the veins of theleg during leg muscle relaxation or during periods of standing.Retrograde flow of blood in a direction opposite to the antegrade flowdirection 100 can create shear stresses on the inside surface of thefourth quadrant 145 causing the commissure 305 of the valve cusp 290 tomove toward the third quadrant 140 with possibly some displacementtoward the overlap inlet end 255 and away from the inner surface 10 ofthe second quadrant 135. Blood flow enters the overlap sinus member 300due to a small pressure driving force that can be approximately 0.1 to 1mm Mercury (Hg) from the overlap outlet end 260 to overlap inlet end 255of the overlap sinus member 300. As blood fills the overlap sinus member300 which is dead ended at the overlap inlet end 255, the valve cusp 290is moved toward the third quadrant 140 of the overlap region 220. Thevalve commissure 305 comes into contact with or adjacent to the innersurface 10 of the third 140 quadrant of the overlap region 220 and stopsany further blood flow in a retrograde direction 100 from occurring inthe overlap through-flow member 295. For the valve commissure 305 toreach from the inner surface of the third quadrant 140 during antegradeflow, to the inner surface of the second quadrant during initiation ofretrograde flow, the valve cusp length 320 should be at leastapproximately one half the overlap through-flow member diameter 310 (seeFIG. 3B). The overlap region length 325 can be approximately the samelength as the valve cusp length 320. Due to the formation methods forthe overlap region 220 of the present venous valve embodiment, theoverlap through-flow member diameter 310 can be approximately one halfthe of the distended vein segment diameter 22 from which it has beenformed, and the overlap region length 325 can be approximately at leastone quarter of the distended vein segment diameter 22 from which it hasbeen formed. The overlap region length 325 could be longer than onequarter of the distended vein segment diameter 22 and could be as largeor larger than the distended vein diameter 22. An excessively longoverlap region length 325 extending more than approximately ten timesthe through-flow member diameter 310 could have the disadvantage thatthe overlap sinus member 300 could have a tendency toward thrombosis dueto blood stasis in that member. All reference numerals correspond tothose elements previously or otherwise described.

[0079] It is understood that the venous valve 210 of the presentinvention is not required to be formed from a distended vein, and othermaterials of construction can also be used. It is further understoodthat the overlap region length 325 used in the previous discussion isused to provide an easily understandable estimate of a valve cusp length320. The valve cusp 290 can be formed with a beveled outlet end (notshown), and is not required to have a valve cusp length 320 equal to theoverlap region length 325.

[0080]FIG. 4 is an isometric view of the overlap region 220 showingexternal wall support 330 such as suture, metal wire, polymeric fiber,ribbon, or other wall support means being place around the outsidesurface 15 of the second 135 and third 140 quadrants at the overlapinlet end 255. Internal wall support 335 such as suture, metal wire,polymeric fiber, polymeric ribbon, or other support means can also beplaced within, sutured within, or placed through the vein wall as shownwithin the second 135 and third 140 quadrants at the overlap outlet end260 or elsewhere throughout all or a portion of the venous valve of thepresent invention. Such internal 335 or external 330 wall support canhelp to resist distension of the overlap inlet 255 or outlet 260 end andensure long term function of the venous valve of this invention. It isunderstood that internal 335 or external 330 wall support can be used ateither or both the overlap inlet or outlet end. Internal 335 or external330 wall support can also be used to support all four quadrant walls ofthe overlap region 220 throughout the entire overlap region 220 betweenthe overlap inlet 255 and outlet 260 ends. Such internal 335 or external330 wall support can extend within a transverse section of the overlapregion 220 as shown in FIG. 4, it can extend axially 60 (see FIG. 1) inthe antegrade flow direction 100, or it can have components in bothdirections. All reference numerals correspond to those elementspreviously or otherwise described.

[0081]FIG. 5A is a partially sectioned view of an embodiment of thevenous valve 210 of the present invention in a flattened condition ascould be found during the formation of the-venous valve. FIG. 5C is apartially sectioned view of an embodiment of the venous valve of thepresent invention with antegrade blood flow passing through it.Sectional views of the inlet 230 or outlet 235 distended vein are shownin a flattened conformation as can be found during venous valveformation in FIG. 5B and in a round conformation providing blood flow inFIG. 5D. FIGS. 5A-5D will be discussed collectively. The zero degreewall line 75 is attached to the 180 degree wall line 125 in the overlapregion 220 forming an overlap zero and 180 degree wall line attachment340 or divisional attachment. The 90 degree wall line 105 is attached tothe 270 degree wall line 130 in the overlap region 220 forming anoverlap 90 and 270 degree wall line attachment 345 or approximationattachment. The venous valve 210 of the present invention is shown tohave an overlap region 220 which is contiguous with the inlet 215 andoutlet 225 transition regions. These regions do not have to becontiguous; they can be attached together or portions of the vein wall20 can be cut and removed as found in a later embodiment. The venousvalve 210 of the present invention is only required to have an overlapregion 220. The inlet 215 and outlet 225 transition regions providesmooth blood transition from inlet distended vein 230 to the overlapregion 220 and from the overlap region 220 to the outlet distended vein235, but are not required in the venous valve 210 of the presentinvention. The inlet transition region 215 can be contiguous with theinlet distended vein 230 if it is formed in situ from an existing nativevein. Similarly, the outlet transition region 225 can be contiguous withthe outlet distended vein 235. Alternately, an embodiment of the venousvalve of the present invention extending from the inlet vein-transitionjunction 25 to the outlet transition-vein junction 30, or anotherembodiment extending only from the overlap inlet end 255 to the overlapoutlet end 260 can be interposed surgically into a vein that requires avenous valve. The venous valve 210 of the present invention can also beconstructed of biological tissue, polymeric material, or autologoustissue taken from another part of the anatomy and formed into the venousvalve. All reference numerals correspond to those elements previously orotherwise described.

[0082]FIG. 6A is a sectional view of the overlap inlet end 255 duringthe formation of the valve of the present invention. The first 110 andsecond 135 quadrants are attached by the overlap inlet end first andsecond quadrant attachment 275. The first 110 and fourth 145 quadrantsare attached by the overlap inlet end first and fourth quadrantattachment 280. The third 140 and fourth 145 quadrants form the overlapthrough-flow member 295. The zero degree wall 70 is attached to the 180degree wall 115 with an overlap inlet end zero and 180 degree wallattachment 350. The overlap inlet end zero and 180 degree wallattachment 350 extends from the overlap inlet 255 to outlet 260 endforming an overlap zero and 180 degree wall line attachment 340 (seeFIG. 5A). The 90 degree wall 80 is attached to the 270 degree wall 120with an overlap inlet end 90 and 270 degree wall attachment 355. Theoverlap inlet end 90 and 270 degree wall attachment 355 extends from theoverlap inlet 255 to outlet 260 end forming an overlap 90 and 270 degreeline attachment 345 (see FIG. 5A). The attachment 275, 280, 350, or 355can be a wall or surface attachment formed using sutures, staples,adhesives, laser welding, or other attachment means or methods describedearlier.

[0083]FIG. 6B is a sectional view of the overlap inlet end 255 duringblood flow in an antegrade flow direction 100 (see FIG. 5C) through theoverlap through-flow member 295. The overlap through-flow memberdiameter 310 can be approximately one half of the inlet or outletdistended vein segment diameter 22 from which it may be formed. Otherconfigurations can similarly be used to form the overlap inlet end ofthe present invention. Other reference numerals are the same as thosefound in FIG. 6A.

[0084]FIG. 7A is a sectional view of the overlap outlet end 260 duringformation. The first 110 and fourth 145 quadrants are attached by theoverlap outlet end first and fourth quadrant attachment 285. The 90degree wall 80 and the 270 degree wall 120 are attached by the overlapoutlet end 90 and 270 degree wall attachment 360. The zero degree wall70 is attached to the 180 degree wall 115 at the overlap outlet end 260by an overlap outlet end zero and 180 degree wall attachment 365. Thefirst 110 and fourth 145 quadrants are attached by the overlap outletend first and fourth quadrant attachment 285. The first quadrant 110 isnot attached to the second quadrant 135 and the third quadrant 140 isnot attached to the fourth quadrant 145 at the overlap outlet end.Surface or wall attachments are formed using materials and methods asdescribed earlier.

[0085]FIG. 7B is a sectional view of the overlap outlet end with bloodflow in an antegrade flow direction 100 (see FIG. 5C) showing theoverlap through-flow member 295 with an overlap through-flow memberdiameter 310. All reference numerals are the same as found in FIG. 7A.

[0086]FIG. 7C is a sectional view of the overlap outlet end withretrograde filling of the overlap sinus member 300. Retrograde fillingof the overlap sinus member 300 causes retrograde flow through thethrough-flow member 295 to reduce significantly or cease. All otherreference numerals are the same as in FIG. 7A.

[0087] As seen in FIGS. 5A and 5C, the venous valve 210 of the presentinvention can have an inlet 215 or an outlet 225 transition region toprovide a smooth transition of blood flow from the inlet distended vein230 or the outlet distended vein 235 to the overlap region 220. Theinlet 215 or outlet 225 transition region can be contiguous with theoverlap region 220 or the transition regions can be contiguous with theinlet 230 or outlet 235 distended veins; or the inlet 215 or outlet 225transition regions can be attached to the overlap region 220, or thetransition regions can be attached to the inlet 230 or outlet 235distended veins using sutures or other attachment means.

[0088]FIGS. 8A and 8B are sectioned views of the inlet transition region215 without blood flow and in a state of being formed. The zero degreewall 70 and the 180 degree wall 115 are shown for reference. As shown inFIG. 8A approximately a 45 degree wall 370 can be attached toapproximately the 315 degree wall 373 at an inlet transition 45 and 315degree wall attachment 382. As shown in FIG. 8B approximately the 20degree wall 384 can be attached to approximately a 340 degree wall 386at an inlet transition 20 and 340 degree wall attachment 388. Additionalinlet transition attachments are made in a similar manner to form a lineof inlet transition wall attachments between the first 110 and fourth145 quadrants that form a tapered line of attachments in the inlettransition region 215 from the overlap region 220 to the inlet distendedvein 230 (see FIGS. 5A and 5B). This tapered line of attachment forms abeveled attachment that extends from the overlap region to the distendedvein with either a straight or curved bevel that directs the blood flowsmoothly from the inlet distended vein 230 to the overlap region 220.All reference numerals correspond to those elements previously orotherwise described.

[0089]FIGS. 8C and 8D are similar to FIGS. 8A and 8B except that theinlet transition region 215 is shown as though blood flow in anantegrade flow direction 100 were present in an inlet transition flowlumen 392. An inlet transition diameter 394 for the inlet transitionflow lumen 392 of FIG. 8C is smaller that an inlet transition diameter396 for an inlet transition flow lumen 402 of FIG. 8D. Inlet transitionexcess tissue 406 is shown extending into the inlet transition flowlumen 392 of FIG. 8C. The inlet transition excess tissue can be attachedto the first or fourth quadrant wall or it can be trimmed off andremoved. All reference numerals correspond to those elements previouslyor otherwise described.

[0090] One embodiment for forming the outlet transition region 225 isshown in FIGS. 9A and 9B. FIGS. 9A and 9B are sectioned views of theoutlet transition region 225 without blood flow and in a state of beingformed. The zero degree wall 70 and the 180 degree wall 115 are shownfor reference. As shown in FIG. 9A approximately the 45 degree wall 370can be attached to approximately the 315 degree wall 373 at an outlettransition 45 and 315 degree wall attachment 411. As shown in FIG. 9Bapproximately the 20 degree wall 384 can be attached to approximatelythe 340 degree wall 386 at the outlet transition 20 and 340 degree wallattachment 416. Additional outlet transition attachments are made in amanner similar to that described for the inlet transition region 215 toform a continuous line of outlet transition wall attachments that form atapered transition from the overlap region 220 to the outlet distendedvein 235. This tapered line of attachment forms a beveled attachmentthat extends from the overlap region to the distended vein with either astraight or curved bevel that directs the blood flow smoothly from theoverlap region 220 to the outlet distended vein 230. Wall and surfaceattachments are formed using materials and methods as discussed earlier.

[0091]FIGS. 9C and 9D are similar to FIGS. 9A and 9B except that theoutlet transition region 225 is shown as though blood flow in anantegrade flow direction 100 were present in an outlet transition flowlumen 421. An outlet transition diameter 426 for the outlet transitionflow lumen 421 of FIG. 9C is smaller that an outlet transition diameter432 for an outlet transition flow lumen 437 of FIG. 9D. Outlettransition excess tissue 442 is shown extending into the outlettransition flow lumen 421 of FIG. 9C. The outlet transition excesstissue 442 can be attached to the first 110 or fourth 145 quadrant wallor it can be trimmed off and removed. All reference numerals correspondto those elements previously or otherwise described.

[0092] One embodiment for forming the inlet transition region 215 isshown in sectional views in FIGS. 10A and 10B. FIG. 10A represents aposition along the inlet transition region similar to that of FIG. 8Aand FIG. 10B represents a position similar to that of FIG. 8B. In FIGS.10A and 10B it is understood that the inlet transition region 215 isshown in a flat conformation such that it may not have blood flow goingthrough it such as during the formation of the venous valve 210 of thepresent invention. FIGS. 10A and 10B show the first 110, second 135,third 140, and fourth 145 quadrants in a similar conformation to thatfound in the overlap region 220 for ease of understanding the formationof the transition region of this embodiment of the present invention. InFIGS. 10A and 10B the zero degree wall 70 and the 180 degree wall 115are not attached, and the 90 degree wall 80 and the 270 degree wall 120are not attached. In FIG. 10A attachment of the first quadrant 110 tothe second quadrant 135 can occur approximately from a 45 degree wall370 to a 135 degree wall 447 forming an inlet transition 45 and 135degree wall attachment 452. An example of an attachment means 278 isshown in FIG. 10A, and can include sutures or other materials orattachment methods or attachment means as described earlier. In FIG. 10Battachment of the first quadrant 110 to the second quadrant 135 canoccur approximately from a 70 degree wall 457 to a 110 degree wall 462forming an inlet transition 70 and 110 degree wall attachment 468. FIGS.10A and 10B represent two sections along the inlet transition region215; the locations for attachment of portions of the first 110 andsecond 135 quadrants are approximate and correspond to positions alongthe axial length of the transition region similar to those found inFIGS. 8A and 8B, respectively. A continuous or intermittent line ofattachments is intended to form a tapered transition for blood flow fromthe inlet distended vein 230 to the overlap inlet end 255 to directblood flow from the inlet distended vein 230 into the overlap inlet end255. It is understood that additional attachments are made along theentire inlet transition region 215 extending from the overlap region 220to the inlet distended vein 230. Inlet transition excess tissue 472 canbe trimmed off or removed provided that the attachments made from thefirst 110 to the second 135 quadrants form a continuous beveled linefrom the overlap region 220 to the inlet distended vein 230 that canwithstand venous blood pressure without leakage. All reference numeralscorrespond to those elements previously or otherwise described.

[0093]FIGS. 10C and 10D are similar to those of FIGS. 10A and 10Brespectively except that the inlet transition region 215 is shown asthough blood flow with an antegrade flow direction 100 (see FIG. 5C)were passing through an inlet transition flow lumen 478 of FIG. 10C. Theinlet transition flow lumen 478 shown in FIG. 10C has an inlettransition diameter 482 that is smaller than the inlet transitiondiameter 488 of the inlet transition flow lumen 492 shown in FIG. 10D.The inlet transition diameter of the inlet transition flow lumen getsprogressively smaller as it extends from the inlet distended vein 230 tothe overlap region 220. The inlet transition excess tissue 472 does notextend into the inlet transition lumen of this embodiment and can be cutoff without affecting the function of the present invention. All otherreference numerals are the same as those in FIGS. 10A and 10B.

[0094] FIGS. 11A-D describe an alternate embodiment of the presentinvention. FIGS. 11A and 11B show a distended vein segment 5 lying flatwith the fourth 145 quadrant and third 140 quadrant lying adjacent tothe first 110 and second 135 quadrant, respectively. The overlap region220 extends from the overlap inlet end 255 to the overlap outlet end260. The inlet transition region 215 can be contiguous with or it can beattached to the overlap inlet end 255 and the outlet transition region225 can be contiguous with or it can be attached to the overlap outletend 260. The inlet distended vein 230 can be contiguous with or it canbe attached to the inlet transition region 215 and the outlet distendedvein 235 can be contiguous with or it can be attached to the outlettransition region 225. The outer surface zero degree line 65 and zerodegree wall 70 and the inner surface zero degree line 55 are shown nearthe top of FIGS. 11A and 11B, and the outer surface 180 degree line 200and 180 degree wall and inner surface 180 degree line 185 are shown nearthe bottom of FIGS. 11A and 11B. An overlap inlet end first and fourthquadrant attachment 280 is formed to attach the first quadrant 110 tothe fourth quadrant 145 at the overlap inlet end 255. This overlap inletend first and fourth quadrant attachment 280 can be made using suture,staples, adhesives, tissue bonding agents, fusion methods, metallicfiber, polymeric fiber, or other surface or wall attachment means. Anexample of such wall or surface attachment means is shown by referencenumeral 278 in FIG. 11B, it can be formed of suture or other material asdescribed earlier for previous embodiments. An overlap outlet end firstand fourth quadrant attachment 285 is formed to attach the firstquadrant 110 to the fourth quadrant 145 at the overlap outlet end 260using surface or wall attachment means. The overlap inlet end and outletend first and fourth quadrant attachments 280 and 285 form the valvecusp attachment. It is understood that such valve cusp attachmentrequires only that a portion of the first 110 and fourth 145 quadrantwalls area 21 be attached together.

[0095] The vein walls 20 of the first 110 and fourth 145 quadrants arecut adjacent to the overlap inlet end first and fourth quadrantattachment 280 at an overlap inlet cut 505 as shown in FIG. 11C.Similarly, the vein walls 20 of the first 110 and fourth 145 quadrantsare cut adjacent to the overlap outlet end first and fourth quadrantattachment 285 at an overlap outlet cut 510 as shown in FIG. 11C.

[0096] The first 110 and fourth 145 quadrants of the overlap region 220undergo an inverted fold 515 to bring the inner surface zero degree line55 into direct contact with the inner surface 180 degree line 185 in theoverlap region 220 as shown in FIG. 11D. The zero degree wall line 75 isattached to the 180 degree wall line 125 at the overlap zero and 180degree wall line attachment 340 forming a divisional attachment in theoverlap region 220 using sutures, staples, bonding agents, fusionmethods or other surface or wall attachment means. This divisionalattachment forms two separate lumens or spaces that do not havesignificant leakage between them. It is understood that the overlap zeroand 180 degree wall line attachment 340 need not be attached from theoverlap inlet 255 to outlet 260 end as long as two tubular members areformed by a divisional attachment, a divisional attachment being asurface or wall attachment that can form two separate flow channels thatdo not allow substantial blood flow to pass across the attachment.

[0097] At the overlap inlet end 255, the first 110 and second 135quadrants are attached forming an overlap inlet end first and secondquadrant attachment 275 or closure attachment as shown in FIG. 11D and11E. The closure attachment does not allow antegrade blood flow to enterbetween the first 110 and second 135 quadrants. In the overlap region220 the outer surface 90 degree line 195 is attached to the outersurface 270 degree line 205 forming the outer surface 90 and 270 degreeline attachment 270 or approximation attachment; this attachment can befound along only a portion of the outer surface 90 and 270 degree lineattachment 270 without affecting the function of the vein valve 210 ofthe present invention. The approximation attachment serves to hold the90 and 270 degree lines in approximation with each other at leastintermittently. The 90 degree wall line 105 and the 270 degree wall line130 are attached in the overlap region 220 to form the overlap 90 and270 degree wall line attachment 345. At this stage of formation, theoverlap region 220 has been formed into one embodiment of the venousvalve 210 of this invention. An inlet 215 or outlet 225 transitionregion can be contiguous with or attached to the overlap region 220. Theoverlap region 220 could also be interpositionally attached between aninlet 230 or outlet 235 distended vein. The overlap outlet end first andfourth quadrant attachment 285 forms a valve cusp free edge orcommissure as described in other previous embodiments of the invention.The inverted fold 515 of the first 110 and fourth 145 quadrants providesthe valve cusp free edge of this embodiment that has the endothelializedsurface folded over such that it approximates the other endothelializedsurface. The endothelialized surface of the commissure is similar to theinner surface of the distended vein. The venous valve of FIG. 11E isshown in a conformation that would provide for antegrade or retrogradeblood flow. All reference numerals correspond to those elementspreviously or otherwise described.

[0098]FIG. 12 is a sectional view at the overlap inlet end 255 showingthe overlap inlet end first and fourth quadrant attachment 280 and theoverlap inlet end first and second quadrant attachment 275. The overlapinlet end first and second quadrant attachment 275 forms a closureattachment that will prevent blood flow in an antegrade direction 100(see FIG. 11E) from entering between the first 110 and second 135quadrants. The overlap through-flow member 295 formed by the third 140and fourth 145 quadrants provides space for antegrade blood flow throughthe overlap region 220 (FIG. 11E).

[0099]FIGS. 13A and 13B are sectional views of the overlap outlet endshowing the overlap outlet end first and fourth quadrant attachment 285.In FIG. 13A the overlap through-flow member 295 provides space for bloodflow in an antegrade direction 100; the valve cusp 290 which is formedfrom the first 110 and fourth 145 quadrants, is in contact with thesecond quadrant 135. During the initiation of retrograde flow, the valvecusp 290 moves into contact with the third quadrant 140 as shown in FIG.13B. Blood will flow into the overlap sinus member 300 causing the valvecusp 290 to prevent continued blood flow in a retrograde direction 315(see FIG. 11E) in the overlap through-flow member 295 as the valve cuspremains in contact with the third quadrant 140. It is understood thatthe valve cusp 290 is formed by an attachment of a portion of the firstquadrant 110 to a portion of the fourth quadrant 145 along a wall lineattachment. This attachment could be formed by attaching a portion of awall area 21 of the first quadrant 110 to a portion of a wall area 21 ofthe fourth quadrant 145. Such a valve cusp 290 could similarly be formedby attachment of two sectors together forming a wall line attachment ora wall area attachment.

[0100] The inlet 215 and outlet 225 transition regions can be formedcontiguously with the overlap region 220 or they can be attached usingsurface or wall attachment means. One method for forming the inlet 215and outlet 225 transition regions contiguously with the overlap region220 is shown in FIGS. 11A-11E. FIG. 11A shows an inlet transitionbeveled attachment 520 that attaches the first 110 and fourth 145quadrants together in the inlet transition region 215. The inlettransition beveled attachment 520 extends from the overlap inlet endfirst and fourth quadrant attachment 280 along a beveled angle to theouter surface zero degree line 65. Similarly, an outlet transitionbeveled attachment 525 is made extending from the overlap outlet endfirst and fourth quadrant attachment 285 along a beveled angle to theouter surface zero degree line 65. These inlet 520 and outlet 525beveled attachments can be made using surface or wall attachment meansas described earlier and can be a curved line attachment; beveled lineattachments are not required to be a straight line.

[0101] An inlet transition beveled cut 530 is made through the first 110and fourth 145 quadrants adjacent to the inlet transition beveledattachment 520 on the side of the attachment nearest to the outersurface zero degree line 65 as shown in FIG. 11C. Similarly, an outlettransition beveled cut 535 is made through the first 110 and fourth 145quadrants adjacent to the outlet transition beveled attachment 520. Theinlet 540 and outlet 545 transition excess tissue can be removed. Theinlet 215 and outlet 225 transition regions provide a smooth contiguoustransition from the overlap region 220 to the inlet 230 and outlet 235distended vein as shown in FIG. 11E.

[0102]FIGS. 14A and 14B FIGS. are sectional views of the inlettransition region 215. The 180 degree wall 115 is shown for reference.As shown in FIG. 14A approximately the 45 degree wall 370 can beattached to approximately the 315 degree wall 373 at an inlet transition45 and 315 degree wall attachment 382. As shown in FIG. 14Bapproximately the 20 degree wall 384 can be attached to approximatelythe 340 degree wall 386 at the inlet transition 20 and 340 degree wallattachment 388. Additional inlet transition attachments are made in amanner to form the inlet transition beveled attachment 520 shown in FIG.11A. An inlet transition diameter 550 for the inlet transition flowlumen 555 of FIG. 14A is smaller that an inlet transition diameter 560for an inlet transition flow lumen 565 of FIG. 14B. The inlet transitionexcess tissue 540 (see FIG. 11C) that was attached to the first 110 orfourth 145 quadrant wall has been trimmed off and removed.

[0103]FIGS. 15A and 15B are sectional views of the outlet transitionregion 225. As shown in FIG. 15A approximately the 45 degree wall 370can be attached to approximately the 315 degree wall 373 at an outlettransition 45 and 315 degree wall attachment 411. As shown in FIG. 15Bapproximately the 20 degree wall 384 can be attached to approximatelythe 340 degree wall 386 at the outlet transition 20 and 340 degree wallattachment 416. Additional outlet transition attachments are made in amanner to form the outlet transition beveled attachment 525 shown inFIG. 11A. An outlet transition diameter 570 for the outlet transitionflow lumen 575 of FIG. 15A is smaller than an outlet transition diameter580 for an outlet transition flow lumen 585 of FIG. 15B. The outlettransition excess tissue 545 (see FIG. 11C) that was attached to thefirst 110 or fourth 145 quadrant wall has been trimmed off and removed.

[0104] FIGS. 16 shows an isometric view of one embodiment of the venousvalve 210 of the present invention. The overlap region 220 iscontiguously joined to the inlet 215 and outlet 225 transition regionswhich are contiguously joined to the inlet 230 and outlet 235 distendedveins, respectively. The inlet 215 and outlet 225 transition regionshave inlet 520 and outlet 525 transition bevel attachments,respectively. The overlap region 220 has an outer surface 90 and 270degree line attachment 270 extending from the overlap inlet end 255 tothe overlap outlet end 260.

[0105] The inner and outer surface line attachments and wall attachmentspresented in this disclosure describe FIGS. 1-16 in a clear manner. Itis understood that in forming the venous valve 210 of the presentinvention the attachments made from one quadrant or sector to anotherare not required to be the surface line or wall line attachments as theyare presented in FIGS. 1-16 and their descriptions. A wall lineattachment for example could occur over only a portion of the overlapregion 220 and it is not required to extend parallel to the centerline40; a surface or wall line attachment is only required to have adirectional component in the direction of the centerline 40 or axialdirection 60. Surface line attachments and wall line attachments can bebeveled or formed at an angle with respect to the centerline 40. Wallline attachments made at the overlap inlet or outlet end can be beveledor formed at an angle with respect to the centerline 40. A portion of awall area 21 from one quadrant or sector can be attached attachment tothe wall area 21 of another quadrant or sector; this surface or wallattachment can be used to form a portion of the valve cusp or form theattachments found on other aspects of the venous valve described in thisdisclosure.

[0106] It is understood that the overlap region of one embodiment can becombined with an inlet or outlet transition region of anotherembodiment. The method of forming the venous valve of this invention canalso involve combinations describing the formation of the overlap regionor transition region from any of the embodiments presented in thisdisclosure. Furthermore, it is understood that the valve of thisinvention can be formed from a combination of autologous tissue used foreither the overlap region or a transition region combined withheterogeneous biological tissue or synthetic material used for anotherportion of the venous valve.

REFERENCE NUMERALS IN DRAWINGS

[0107]5 Distended Vein Segment

[0108]10 Inner Surface

[0109]15 Outer Surface

[0110]20 Vein Wall

[0111]21 Wall Area

[0112]22 Distended Vein Segment Diameter

[0113]25 Inlet Vein-Transition Junction

[0114]30 Outlet Transition-Vein Junction

[0115]35 Zero Degree Radian

[0116]40 Centerline

[0117]45 Inner Surface Zero Degree Point

[0118]50 Outer Surface Zero Degree Point

[0119]55 Inner Surface Zero Degree Line

[0120]60 Axial Direction

[0121]65 Outer Surface Zero Degree Line

[0122]70 Zero Degree Wall

[0123]75 Zero Degree Wall Line

[0124]80 90 Degree Wall

[0125]85 90 Degree Radian

[0126]90 Clockwise

[0127]95 Angle

[0128]100 Antegrade Flow Direction

[0129]105 90 Degree Wall Line

[0130]110 First Quadrant

[0131]115 180 Degree Wall

[0132]120 270 Degree Wall

[0133]125 180 Degree Wall Line

[0134]130 270 Degree Wall Line

[0135]135 Second Quandrant

[0136]140 Third Quandrant

[0137]145 Fourth Quandrant

[0138]150 Inner Surface 90 Degree Point

[0139]155 Inner Surface 180 Degree Point

[0140]160 Inner Surface 270 Degree Point

[0141]165 Outer Surface 90 Degree Point

[0142]170 Outer Surface 180 Degree Point

[0143]175 Outer Surface 270 Degree Point

[0144]180 Inner Surface 90 Degree Line

[0145]185 Inner Surface 180 Degree Line

[0146]190 Inner Surface 270 Degree Line

[0147]195 Outer Surface 90 Degree Line

[0148]200 Outer Surface 180 Degree Line

[0149]205 Outer Surface 270 Degree Line

[0150]210 Venous Valve

[0151]215 Inlet Transition Region

[0152]220 Overlap Region

[0153]225 Outlet Transition region

[0154]230 Inlet Distended Vein

[0155]235 Outlet Distended Vein

[0156]240 Overlap Transverse Diameter

[0157]245 Inlet Distended Vein Diameter

[0158]250 Outlet Distended Vein Diameter

[0159]255 Overlap Inlet End

[0160]260 Overlap Outlet End

[0161]265 Inner Surface Zero and 180 Degree Line Attachment

[0162]268 Attachment Means

[0163]270 Outer Surface 90 and 270 Degree Line Attachment

[0164]275 Overlap Inlet End First and Second Quandrant Attachment

[0165]278 Attachment Means

[0166]280 Overlap Inlet End First and Fourth Quandrant Attachment

[0167]285 Overlap Outlet End First and Fourth Quandrant Attachment

[0168]290 Valve Cusp

[0169]295 Overlap Through-Flow Member

[0170]300 Overlap Sinus Member

[0171]305 Commissure

[0172]310 Overlap Through-Flow Member Diameter

[0173]315 Retrograde Flow Direction

[0174]320 Valve Cusp Length

[0175]325 Overlap Region Length

[0176]330 External Wall Support

[0177]335 Internal Wall Support

[0178]340 Overlap Zero and 180 Degree Wall Line Attachment

[0179]345 Overlap 90 and 270 Degree Wall Line Attachment

[0180]350 Overlap Inlet End Zero and 180 Degree Wall Attachment

[0181]355 Overlap Inlet End 90 and 270 Degree Wall Attachment

[0182]360 Overlap Outlet End 90 and 270 Degree Wall Attachment

[0183]365 Overlap Outlet End Zero and 180 Degree Wall Attachment

[0184]370 45 Degree Wall

[0185]373 315 Degree Wall

[0186]382 Inlet Transition 45 and 315 Degree Wall Attachment

[0187]384 20 Degree Wall

[0188]386 340 Degree Wall

[0189]388 Inlet Transition 20 and 340 Degree Wall Attachment

[0190]392 Inlet Transition Flow Lumen

[0191]394 Inlet Transition Diameter

[0192]396 Inlet Transition Diameter

[0193]402 Inlet Transition Flow Lumen

[0194]406 Inlet Transition Excess Tissue

[0195]411 Outlet Transition 45 and 315 Degree Wall Attachment

[0196]416 Outlet Transition 20 and 340 Degree Wall Attachment

[0197]421 Outlet Transition Flow Lumen

[0198]426 Outlet Transition Diameter

[0199]432 Outlet Transition Diameter

[0200]437 Outlet Transition Flow Lumen

[0201]442 Outlet Transition Excess Tissue

[0202]447 135 Degree Wall

[0203]452 Inlet Transition 45 and 135 Degree Wall Attachment

[0204]457 70 Degree Wall

[0205]462 110 Degree Wall

[0206]468 Inlet Transition 70 and 110 Degree Wall Attachment

[0207]472 Inlet Transition Excess Tissue

[0208]478 Inlet Transition Flow Lumen

[0209]482 Inlet Transition Diameter

[0210]488 Inlet Transition Diameter

[0211]492 Inlet Transition Flow Lumen

[0212]505 Verlap Inlet Cut

[0213]510 Overlap Outlet Cut

[0214]515 Inverted Fold

[0215]520 Inlet Transition Beveled Attachment

[0216]525 Outlet Transition Beveled Attachment

[0217]530 Inlet Transition Beveled Cut

[0218]535 Outlet Transition Beveled Cut

[0219]540 Inlet Transition Excess Tissue

[0220]545 Outlet Transition Excess Tissue

[0221]550 Inlet Transition Diameter

[0222]555 Inlet Transition Flow Lumen

[0223]560 Inlet Transition Diameter

[0224]565 Inlet Transition Flow Lumen

[0225]570 Outlet Transition Diameter

[0226]575 Outlet Transition Flow Lumen

[0227]580 Outlet Transition Diameter

[0228]585 Outlet Transition Flow Lumen

[0229] Various modifications can be made to the present inventionwithout departing from the apparent scope hereof:

We claim:
 1. A venous valve for directing antegrade blood flow in anautologous vein of the body that requires a venous valve, said venousvalve comprising a tubular conduit means from which said venous valve isformed, said tubular conduit means having a tubular conduit inlet end, atubular conduit outlet end, and a tubular conduit wall; a portion of thetubular conduit wall being attached to another portion of the tubularconduit wall substantially from the inlet to the outlet end of saidtubular conduit means forming two tubular members, a first tubularmember having a first tubular member wall, and a second tubular memberhaving a second tubular member wall; a portion of said first tubularmember wall being attached to a portion of said second tubular memberwall to position a substantial portion of said first tubular member wallin approximation with a substantial portion of said second tubularmember wall with an approximation attachment; an inlet end of saidsecond tubular member having a closure attachment to prevent antegradeblood flow from entering said second tubular member and to preventretrograde blood flow from passing through said second tubular member; aportion of said first tubular member wall being attached via a valvecusp attachment to a portion of said second tubular member wall atapproximately the outlet end of said tubular conduit member to form atleast a portion of a valve cusp, said valve cusp directing retrogradeblood flow into an outlet end of said second tubular member andpreventing substantial retrograde blood flow through said first tubularmember; whereby said venous valve directs antegrade blood flow from saidtubular conduit inlet end to said tubular conduit outlet end andprevents substantial retrograde blood flow from said tubular conduitoutlet end to said tubular conduit inlet end.
 2. The venous valve ofclaim 1 wherein said tubular conduit means is an autologous vein segmentwith endothelium on at least a portion of an inner surface.
 3. Thevenous valve of claim 2 wherein said autologous vein segment iscontiguous with the autologous vein that requires a venous valve.
 4. Thevenous valve of claim 2 wherein said valve cusp has an endothelializedsurface.
 5. The venous valve of claim 2 wherein said valve cusp has aninverted fold with endothelium covering said valve cusp.
 6. The venousvalve of claim 1 further comprising an inlet transition region joined tosaid tubular conduit means and extending from said tubular conduit inletend to an inlet end of the autologous vein requiring a venous valve,said inlet transition region having a tapered tubular shape with aninlet transition lumen;
 7. The venous valve of claim 1 furthercomprising an outlet transition region joined to said tubular conduitmeans extending from said tubular conduit outlet end to an outlet end ofthe autologous vein requiring a venous valve, said outlet transitionregion having a tapered tubular shape with an outlet transition lumen.8. The venous valve of claim 1 further comprising; A. an inlettransition region joined to said tubular conduit means extending fromsaid tubular conduit inlet end to an inlet end of the autologous veinrequiring a venous valve, said inlet transition region having a taperedtubular shape with an inlet transition lumen, and; B. an outlettransition region joined to said tubular conduit means extending fromsaid tubular conduit outlet end to an outlet end of the autologous veinrequiring a venous valve, said outlet transition region having a taperedtubular shape with an outlet transition lumen.
 9. The venous valve ofclaim 8 wherein said inlet and outlet transition regions are formed froman autologous vein segment.
 10. The venous valve of claim 9 wherein saidautologous vein segment is contiguous with the autologous vein thatrequires a venous valve.
 11. The venous valve of claim 6 wherein saidinlet transition region has an inlet transition beveled attachmentformed by the attachment of a portion of a first sector to a portion ofa second sector along a wall line that extends from said tubular conduitinlet end to the inlet end of the autologous vein requiring a venousvalve.
 12. The venous valve of claim 6 wherein excess inlet transitiontissue extends outside said inlet transition beveled attachment andoutside said inlet transition lumen.
 13. The venous valve of claim 12wherein said excess inlet transition tissue is cut off or removed. 14.The venous valve of claim 11 wherein excess inlet transition tissueextends inside said inlet transition beveled attachment and inside saidinlet transition lumen.
 15. The venous valve of claim 7 wherein saidoutlet transition region has an outlet transition beveled attachmentformed by the attachment of a portion of a first sector to a portion ofa second sector along a wall line that extends from said tubular conduitoutlet end to the outlet end of the autologous vein requiring a venousvalve.
 16. The venous valve of claim 15 wherein excess outlet transitiontissue extends inside said outlet transition attachment and inside saidinlet transition lumen.
 17. The venous valve of claim 1 wherein saidvalve cusp has a valve cusp length in a generally axial direction thatis greater than one half of a diameter of said first tubular member. 18.The venous valve of claim 1 wherein said first tubular member has afirst tubular member diameter that is less than the diameter of theautologous vein that requires a venous valve.
 19. The venous valve ofclaim 1 wherein said approximation attachment, said closure attachment,and said valve cusp attachment is comprised of attachment means takenfrom a group which includes staples, suture, adhesives, bonding agents,metal strand material, polymeric strand material, laser fusion, orthermal fusion.
 20. The venous valve of claim 1 wherein said tubularconduit means has a wall support means attached to prevent distension ofat least a portion of said tubular conduit means.
 21. The venous valveof claim 1 wherein said first tubular member or said second tubularmember have wall support means attached to said first tubular memberwall or said second tubular member wall between said inlet and outletend of said first or second tubular member to prevent distension. 22.The venous valve of claim 1 wherein said tubular conduit means is anonautologous biological conduit.
 23. The venous valve of claim 1wherein said tubular conduit means is an autologous tissue formed into atubular shape.
 24. The venous valve of claim 1 wherein said tubularconduit means is a polymeric conduit.
 25. The venous valve of claim 1wherein said tubular conduit means is a conduit formed of a compositematerial.
 26. A venous valve for directing antegrade blood flow in avascular conduit of the body that requires a venous valve, said venousvalve comprising a tubular conduit means from which said venous valve isformed, said tubular conduit means having a tubular conduit inlet end, atubular conduit outlet end, and a tubular conduit wall, said tubularconduit wall having tubular conduit wall lines that extend within saidtubular conduit wall and having a tubular conduit axial directioncomponent, said tubular conduit wall being divided into sectors; atleast a portion of a wall line of one sector forming a divisionalattachment to at least a portion of a wall line of another sector toform two tubular members, a first tubular member having a first tubularmember wall, and first tubular member wall lines within said firsttubular member wall with an axial direction component, and a secondtubular member having a second tubular member wall and second tubularmember wall lines within said second tubular member wall with an axialdirection component; at least a portion of at least one of said firsttubular member wall lines forms an approximation attachment to at leasta portion of at least one of said second tubular member wall lines toposition at least a portion of said first tubular member wall inapproximation with at least a portion of said second tubular memberwall; at least a portion of said second tubular member wall at an inletend of said second tubular member forms a closure attachment to preventantegrade blood flow from entering said second tubular member and toprevent retrograde blood flow from passing through said second tubularmember; a portion of said first tubular member wall forms a valve cuspattachment to a portion of said second tubular member wall to form atleast a portion of a valve cusp, said valve cusp directing retrogradeblood flow into said second tubular member and preventing retrogradeblood flow through said first tubular member; whereby said venous valvedirects antegrade blood flow from said tubular conduit inlet end to saidtubular conduit outlet end and prevents retrograde blood flow from saidtubular conduit outlet end to said tubular conduit inlet end.
 27. Avenous valve for directing antegrade blood flow in a vascular conduit ofthe body that requires a venous valve, said venous valve comprising atubular means from which said venous valve is formed, said tubular meanshaving a tubular conduit inlet end, a tubular conduit outlet end, and atubular conduit wall, said tubular conduit wall having tubular conduitwall lines that extend within said tubular conduit wall and having atubular conduit axial direction component; a portion of one wall linebeing attached to a portion of another wall line forming two tubularmembers, a first tubular member having a first tubular member wall, andfirst tubular member wall lines with an axial direction component, and asecond tubular member having a second tubular member wall and secondtubular member wall lines with an axial direction component; a portionof at least one of said first tubular member wall lines being attachedto a portion of at least one of said second tubular member wall lines toposition a portion of said first tubular member wall in approximationwith a portion of said second tubular member wall; a portion of saidsecond tubular member wall at a first end of said second tubular memberbeing attached to prevent antegrade blood flow from entering said firstend of said second tubular member and to prevent retrograde blood flowfrom passing through said second tubular member; a portion of said firsttubular member being attached to a portion of said second tubular memberwall to form at least a portion of a valve cusp, said valve cuspdirecting retrograde blood flow into a second end of said second tubularmember and preventing retrograde blood flow through said first tubularmember; whereby said venous valve directs antegrade blood flow from saidtubular conduit inlet end to said tubular conduit outlet end andprevents retrograde blood flow from said tubular conduit outlet end tosaid tubular conduit inlet end.
 28. A venous valve for directingantegrade venous blood flow in the vascular system of the body towardthe heart through an autologous vein with that requires a venous valve,said venous valve comprising; A. a tubular conduit means from which saidvenous valve is formed, said tubular conduit means having a tubularconduit inlet end, a tubular conduit outlet end, a tubular conduit axialdirection, a tubular conduit axial length, a tubular conduit diameter,and a tubular conduit wall, said tubular conduit wall having tubularconduit wall lines that extend within said tubular conduit wall andhaving a tubular conduit axial direction component, said tubular conduitwall being divided into sectors, said tubular conduit wall having anInner surface and an outer surface; B. a divisional attachment formed bythe attachment of at least a portion of a first sector wall line of afirst sector to at least a portion of a second sector wall line of asecond sector along at least a portion of the axial length of saidtubular means to form two tubular members of said generally tubularmeans, a first tubular member and a second tubular member, said firsttubular member having a first tubular member inlet end, first tubularmember outlet end, first tubular member wall, and first tubular memberwall lines within said first tubular member wall with a first tubularmember axial direction component, and said second tubular member havinga second tubular member inlet end, second tubular member outlet end,second tubular member wall, and second tubular member wall lines withinsaid second tubular member wall with a second tubular member axialdirection component; C. an approximation attachment formed by theattachment of at least a portion of at least one of said first tubularmember wall lines to at least a portion of at least one of said secondtubular member wall lines to position at least a portion of said firsttubular member wall in approximation with at least a portion of saidsecond tubular member wall; D. a closure attachment formed by theattachment of at least a portion of said second tubular member wall atsaid second tubular member inlet end to substantially prevent antegradeblood flow from entering said second tubular member inlet end and tosubstantially prevent retrograde flow from flowing through said secondtubular member; E. a valve cusp attachment formed by the attachment of aportion of said first tubular member wall to a portion of said secondtubular member wall to form at least a portion of a valve cusp, saidvalve cusp substantially preventing retrograde blood flow through saidfirst tubular member.
 29. A method for forming a venous valve fordirecting antegrade venous blood flow through a vein, said methodcomprising the steps of; A. identifying and isolating a tubular conduitmeans from which said venous valve is formed, said tubular conduit meanshaving a tubular conduit inlet end, a tubular conduit outlet end, and atubular conduit wall; B. forming a divisional attachment between twoportions of tubular conduit to form two tubular members, a first andsecond tubular member, with first and second tubular member walls,respectively; C. forming a closure attachment at an inlet end of saidsecond tubular member to prevent antegrade blood flow from entering saidsecond tubular member; D. forming a valve cusp attachment by attaching aportion of wall of said first tubular member wall to a portion of wallof said second tubular member wall using attachment means to form atleast a portion of a valve cusp, said valve cusp directing retrogradeblood flow into an outlet end of said second tubular member andsubstantially preventing retrograde blood flow through said firsttubular member; E. forming an approximation attachment by attaching atleast a portion of said first tubular member wall to at least a portionof said second tubular member wall using attachment means to position atleast a portion of said first tubular member wall in approximation withat least a portion of said second tubular member wall; F. therebydirecting antegrade blood flow through said first tubular member andsubstantially preventing retrograde blood flow through said firsttubular member.
 30. A method for forming a venous valve for directingantegrade venous blood flow through a vein, said method comprising thesteps of; A. identifying and providing a tubular conduit means fromwhich said venous valve is formed, said tubular conduit means having atubular conduit inlet end, a tubular conduit outlet end, and a tubularconduit wall, said tubular conduit wall having tubular conduit walllines that extend within said tubular conduit wall and having a tubularconduit axial direction component, said tubular conduit wall beingdivided into sectors; B. forming an inlet valve cusp attachment byattaching a portion of a tubular conduit wall from a first sector to atubular conduit wall of a second sector at approximately the inlet endof said tubular conduit means to form at least a portion of a valvecusp; C. forming an outlet valve cusp attachment by attaching a portionof a tubular conduit wall from a first sector to a tubular conduit wallof a second sector at approximately the outlet end of said tubularconduit means to form at least a portion of a valve cusp; D. cuttingsaid tubular conduit means adjacent to and in a retrograde directionfrom said inlet valve cusp attachment, and cutting said tubular conduitmeans adjacent to an in an antegrade direction from said outlet valvecusp attachment; E. invert fold the first and second sectors such that afirst wall line located adjacent to said first and second sectors is inapposition to a second wall line that is not adjacent to said first andsecond sectors; F. forming a divisional attachment by attaching at leasta portion of said first wall line to at least a portion of said secondwall line to form two tubular members, a first tubular member having afirst tubular member wall and providing an antegrade blood through-flowpath, and a second tubular member having a second tubular member walland providing at least a portion of a sinus member; G. forming a closureattachment by attaching said second tubular member wall at approximatelythe inlet end of said tubular conduit means using attachment means toprevent antegrade blood flow from entering said second tubular memberinlet end and to prevent retrograde blood flow from passing through saidsecond tubular member; H. forming an approximation attachment byattaching at least a portion of said first tubular member wall to atleast a portion of said second tubular member wall using attachmentmeans to position at least a portion of said first tubular member wallin approximation with at least a portion of said second tubular memberwall thereby causing said valve cusp to prevent retrograde blood flowthrough said first tubular member and allow antegrade blood flow throughsaid first tubular member;
 31. The method of claim 29 wherein saidvenous valve is formed with the tubular conduit means in substantially aflat conformation.
 32. The method of claim 29 wherein said attachmentmeans includes suture, staples, metallic fiber, polymeric fiber,adhesives, biological bonding agents, laser fusion methods, and thermalfusion methods.
 33. The method of claim 29 wherein said tubular conduitmeans is an autologous vein segment with an inlet end and an outlet end,said autologous vein segment being contiguous with the autologous veinrequiring a venous valve and the formation of said venous valve beingconducted in situ.
 34. The method of claim 29 wherein said tubularconduit means is not an autologous vein segment contiguous with theautologous vein requiring a venous valve, said tubular conduit meansbeing formed into said venous valve and implanted interpositionally intothe autologous vein that requires a venous valve using attachment meansto provide a leak free seal between said venous valve and saidautologous vein requiring a venous valve.
 35. The method of claim 33further comprising the steps of; A. forming an inlet transition regionfrom said autologous vein segment, said inlet transition region having atapered tubular shape with an inlet transition lumen and extending fromsaid tubular conduit inlet end to said autologous vein requiring avenous valve; B. forming on outlet transition region from saidautologous vein segment., said outlet transition region having a taperedtubular shape with and outlet transition lumen and extending from saidtubular conduit outlet end to said autologous vein requiring a venousvalve.
 36. The method of claim 30 wherein said tubular conduit means isan autologous vein segment with an inlet end and an outlet end, saidautologous vein segment being that contiguous with the autologous veinrequiring a venous valve and the formation of said venous valve is insitu.
 37. The method of claim 36 further comprising the steps of; A.forming an inlet transition region from said autologous vein segment,said inlet transition region having a tapered tubular shape with aninlet transition lumen and extending from said tubular conduit inlet endto said autologous vein requiring a venous valve; B. forming an outlettransition region from said autologous vein segment, said outlettransition region having a tapered tubular shape with and outlettransition lumen and extending from said tubular conduit outlet end tosaid autologous vein requiring a venous valve.
 38. The method of claim33 wherein said forming of said valve cusp attachment comprises thesteps of; A. forming a transverse attachment along a portion of saidinlet end and said outlet end of said autologous vein segment; B.cutting said autologous vein segment adjacent to said inlet and outletend; C. forming an inverted fold between said inlet and outlet end ofsaid autologous vein segment, thereby providing a valve cusp that isentirely endothelialized.
 39. The method of claim 35 further comprisingthe steps; A. forming an inlet transition beveled attachment byattaching a portion of a first sector to a portion of a second sectoralong a wall line that extends from said tubular conduit inlet end tothe autologous vein requiring a venous valve. B. forming excess tissueoutside said inlet transition attachment and outside said inlettransition lumen.
 40. The method of claim 39 further comprising thesteps of cutting off and removing said excess tissue using scissors,scalpel, or other cutting means.
 41. The method of claim 35 furthercomprising the steps; A. forming an inlet transition beveled attachmentby attaching a portion of a first sector to a portion of a second sectoralong a wall line that extends from said first tubular member inlet endand said second tubular member inlet end to the autologous veinrequiring a venous valve. B. forming an outlet transition attachment byattaching a portion of a first sector to a portion of a second sectoralong a line that extends from said first tubular member outlet end andsaid second tubular member outlet end to the autologous vein requiring avenous valve. C. forming excess tissue outside said inlet and saidoutlet transition attachment and outside said inlet and outlettransition lumen.
 42. The method of claim 35 further comprising thesteps; A. forming an inlet transition beveled attachment by attaching aportion of a first sector to a portion of a second sector along a wallline that extends from said first tubular member inlet end and saidsecond tubular member inlet end to the autologous vein requiring avenous valve. B. forming an outlet transition beveled attachment byattaching a portion of a first sector to a portion of a second sectoralong a wall line that extends from said first tubular member outlet endand said second tubular member outlet end to the autologous veinrequiring a venous valve. C. forming excess tissue inside said inlet andsaid outlet transition attachment and inside said inlet and outlettransition lumen.